MOSCOW (Reuters) - Russia told residents on Saturday to stay away from a pristine beach in the Far East due to unexplained water pollution that Greenpeace said was evidence of an “ecological disaster” and had caused some surfers to break into a fever and vomit. The cause of the pollution off the coast of Kamchatka region was not immediately clear. Authorities said preliminary tests had found elevated levels of oil products and the chemical phenol and Greenpeace told them to urgently find the source. “The only thing it is possible to say now is there are contaminative substances in the water. Final tests are not ready yet,” Kamchatka’s regional governor Vladimir Solodov said. Greenpeace suggested the pollution could have happened weeks ago. It said the pollution was noticed over the course of several weeks by people on Khalaktyrsky beach, a section of Pacific coastline covered with black volcanic sand that is dozens of kilometers long and popular with tourists. “The water... has changed colour and become unsafe for people’s health. For several weeks people who were in contact with the water have experienced negative consequences,” it said in a statement. After getting into the water, people have complained of sore throats, worsening eyesight, dry eyes, nausea, physical weakness, vomiting and fever, it said. Dead octopuses and other sea life could be seen washed up on the beach in videos posted on Instagram and reposted by Greenpeace. Reuters could not immediately confirm that the videos showed current environmental damage from the scene. “The fact that dead animals can be found along the entire coastline confirms the seriousness of the situation,” Greenpeace said. Local authorities said on Saturday they had inspected the beach and that the animals had washed up because of a storm. Earlier this week, the region’s acting natural resources minister Alexei Kumarkov said tests showed levels of oil products and phenol were 3.6 and 2.5 times higher than the norm.